Dear Aaron,
In message 2609392.0ByMiX4J6F@flash you wrote:
U-Boot OS might be fun for people writing applications where they want bare metal (i.e. hard real-time), though that's already provided with the API and examples.
Urgh... no!!! U-Boot is definitely *not* suitable for any kind of real-time tasks. By design it implements strict single-tasking with usally polling hardware access only. No multi-tasking, no interrupts, no locking, no timers, nothing...
You can't get much more arms length than that except perhaps requiring U-Boot to use an interrupt. They are by just about any definition, completely separate binaries. I'm no lawyer, but reading the GPL FAQ I think we fall well within the arms length separation.
Definitely not. You could not implement any of this without heavily relyin on and deriving from internal interfaces of U-Boot which are not exported for non-GPL use.
Best regards,
Wolfgang Denk